Sequence aware functional encryption and its application in searchable encryption

As a new broad vision of public-key encryption systems, functional encryption provides a promising solution for many challenging security problems such as expressive access control and searching on encrypted data. In this paper, we present two Sequence Aware Function Encryption (SAFE) schemes. Such a scheme is very useful in many forensics applications where the order (or pattern) of the attributes forms an important characteristic of an attribute sequence. Our first scheme supports the matching of two bit strings, while the second scheme can support the matching of general characters. These two schemes are constructed based on the standard Decision Linear and Decision Bilinear Diffie-Hellman assumptions. In addition, we show that our SAFE schemes can also provide the additional feature of attribute-hiding, which is desirable in forensics applications. Moreover, we give an interesting application of SAFE schemes in constructing Sequential Aware Keyword Search (SAKS) schemes.